Effectiveness of a telehealth-delivered clinician-supported exercise and weight loss program for hip osteoarthritis – protocol for the Better Hip randomised controlled trial

Background Hip osteoarthritis (OA) is a leading cause of chronic pain and disability worldwide. Self-management is vital with education, exercise and weight loss core recommended treatments. However, evidence-practice gaps exist, and service models that increase patient accessibility to clinicians who can support lifestyle management are needed. The primary aim of this study is to determine the effectiveness of a telehealth-delivered clinician-supported exercise and weight loss program (Better Hip) on the primary outcomes of hip pain on walking and physical function at 6 months, compared with an information-only control for people with hip OA. Methods A two-arm, parallel-design, superiority pragmatic randomised controlled trial. 212 members from a health insurance fund aged 45 years and over, with painful hip OA will be recruited. Participants will be randomly allocated to receive: i) Better Hip; or ii) web-based information only (control). Participants randomised to the Better Hip program will have six videoconferencing physiotherapist consultations for education about OA, prescription of individualised home-based strengthening and physical activity programs, behaviour change support, and facilitation of other self-management strategies. Those with a body mass index > 27 kg/m2, aged < 80 years and no specific health conditions, will also be offered six videoconferencing dietitian consultations to undertake a weight loss program. Participants in the control group will be provided with similar educational information about managing hip OA via a custom website. All participants will be reassessed at 6 and 12 months. Primary outcomes are hip pain on walking and physical function. Secondary outcomes include measures of pain; hip function; weight; health-related quality of life; physical activity levels; global change in hip problem; willingness to undergo hip replacement surgery; rates of hip replacement; and use of oral pain medications. A health economic evaluation at 12 months will be conducted and reported separately. Discussion Findings will determine whether a telehealth-delivered clinician-supported lifestyle management program including education, exercise/physical activity and, for those with overweight or obesity, weight loss, is more effective than information only in people with hip OA. Results will inform the implementation of such programs to increase access to core recommended treatments. Trial registration Australia New Zealand Clinical Trials Registry (ACTRN12622000461796).


Background
Osteoarthritis (OA) is a leading cause of chronic pain and disability worldwide and is strongly linked to many other health conditions such as obesity, diabetes and heart disease [1].Around 2.1 million Australians have OA, with a 58% increase expected by 2032 due to an ageing population and escalating obesity rates [2].Osteoarthritis at the hip is common, affecting one in four adults over their lifetime [3].In 2012, Australian expenditure on OA was $3.75 billion, [2] of which hip replacement for endstage disease was a major contributor.Of the 38,606 primary hip replacements performed in Australia in 2020, 77% were in people with overweight/obesity [4].Clinical guidelines emphasise lifestyle management, including education, exercise and weight loss (for those with overweight/obesity) as core OA treatments [5,6] because they improve pain, function and quality of life [7] and reduce need for hip replacement [8].
Osteoarthritis is predominately managed in the community, yet community care is inadequate, with 57% of people receiving inappropriate care [9].For many, access to healthcare and support for lifestyle management is challenging, especially in regional and remote regions, where services can be limited or non-existent.Underutilisation of lifestyle management and over-utilisation of drugs (including opioids) and surgery are unsustainable problems [10,11].For example, our analysis of general practitioner (GP) data from 2010 to 2016 (2598 consultations for hip OA [12]) found prescription rates for drugs were much higher than lifestyle management (75 vs 20 per 100 hip OA encounters).Most referrals were to orthopaedic surgeons (65%) with few to physiotherapists (19%) and even fewer to dietitians (0.5%).Meta-analysis [13] shows under-utilisation of lifestyle treatment for OA is a global problem.
There are many barriers to uptake of, and engagement with, exercise and weight loss for people with OA [14,15] Pain, fatigue and stiffness hinder engagement with exercise.People with OA tend to have a sense that their physical capabilities are limited, and this then becomes self-fulfilling when their physical fitness declines due to decreased activity [16].A lack of knowledge about the beneficial effects of exercise on OA symptoms and disease progression persists in people with OA, with exercise tending to be viewed as not effective as a treatment, or even harmful to the joints [14,16].These inaccurate beliefs hinder people with OA from being physically active.Barriers to engagement with exercise also include a lack of motivation and prioritisation of exercise, feelings of resignation and helplessness about the disease, and a lack of support from health professionals [14,16].Lack of motivation and support from health professionals also have been reported as the greatest barriers to weight loss in people with OA [15].Effective communication and clinician support are vital to correct misperceptions and to improve self-belief and motivation [17], yet clinicians often adopt a biomedical framework that is not patient-centered and does not facilitate self-management [15].We identified many barriers to implementing high value OA care amongst 1886 clinicians (GPs, nurses, physiotherapists) [18], including limited skills and confidence in exercise, nutrition, and behavioural counselling.Further, people with hip OA, especially in regional and rural areas, have difficulty accessing physiotherapists, (e.g.101 physiotherapists/100,000 people in Australian cities, compared to just 38 in remote areas) and dietitians (e.g.only 5071 accredited practicing dietitians in Australia, mostly urban).Even in metropolitan areas, travelling to consult a clinician can be difficult for people with OA due to pain and restricted mobility.Accordingly, there are calls for increased implementation of evidencebased telehealth OA services to improve access to care and reduce inequity [19].
A comprehensive multi-disciplinary program that increases access to best-practice exercise and nutrition care is required for people with hip OA.Telehealth offers an acceptable, equitable and sustainable delivery mode to achieve this aim.Better Hip was adapted from a program we developed for knee OA (Better Knee, Better Me) that was shown to be effective in improving pain and function in a randomised controlled trial (RCT) [20,21] and which has now been rolled out by a major Australian health insurer (Medibank) to their members.With end-users we adapted Better Knee, Better Me for hip OA by asking four physiotherapists for their input on modifications to the physiotherapy protocol and sought consumer and Medibank feedback on changes to the participant resources to make them targeted to hip OA and weight loss in this population.We then piloted the Better Hip program in 18 people.Retention was excellent with 89% completing 6-month follow-up.All attended all 6 dietitian consults and 89% attended ≥5 of the six physiotherapy consults.Most (88%) were "extremely satisfied" with the program [22].Participants in the pilot were interviewed, and their experiences were used to refine the final Better Hip program.Better Hip incorporates education, exercise/physical activity, self-management support and, for those who need it, dietary intervention for weight loss (a ketogenic very low energy diet (VLED) demonstrated to be effective for achieving rapid and substantial weight loss) [23].The program includes videoconference consultations with physiotherapists and dietitians, behaviour change support, and education/resources to facilitate sustained exercise and nutrition lifestyle behaviour change by patients.
Thus, this study aims to determine the effectiveness of the Better Hip telehealth-delivered clinician-supported program on the primary outcomes of change in hip pain on walking and change in physical function at 6 months, compared with an information-only control, for people with hip OA.We also aim to determine the effectiveness of the Better Hip program on primary outcomes at 12 months and secondary outcomes at 6-and 12-months as well as conduct a cost effectiveness analysis of the program at 12 months.

Study design
The Better Hip trial is a two-group, parallel-design, superiority pragmatic RCT conducted across Australia, with nested qualitative studies and health economic evaluation.The trial is designed according to SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines [24] and principles of Good Clinical Practice.It has been prospectively registered (ACTRN12622000461796) and will be reported according to the CONSORT statement and relevant extensions [25].A study Data Safety and Monitoring Committee has been established consisting of a doctor with expertise in weight loss, a biostatistician and a physiotherapist in clinical practice, none of whom are involved in the study, have any conflicts of interest, or will benefit from the results.The committee will receive a study report every 3 months but will not meet unless warranted.There is no planned interim analysis or stopping guidelines.We will describe any protocol amendments in our internal trial protocol document, notify the institutional ethics committee and if appropriate update the trial registry.

Participants
We will recruit community participants from members of one of Australia's largest private health insurers, Medibank Private Limited (Medibank) (approximately 3.7 million members).A total of 212 participants across Australia with chronic hip pain consistent with a clinical diagnosis of hip OA [6] will be recruited via marketing campaigns run by Medibank, leveraging channels such as its website, email newsletters, health promotion emails and social media.
Inclusion criteria are as follows: i) National Institute for Health and Care Excellence [6] clinical criteria for OA: -age ≥ 45 years; -activity-related hip joint pain; and -no morning hip stiffness, or morning hip stiffness ≤30 mins; ii) report hip pain on most days for ≥3 months; iii) report average hip pain during walking in the past week ≥4 on an 11-point numerical rating scale (NRS; 0 = no pain, 10 = worst pain possible); iv) access to a computer/laptop/tablet with internet connection and a webcam for videoconferencing consultations; v) own a smartphone (for pairing with activity tracker); vi) willing and able to participate in video consultations for physiotherapy and dietitian appointments; vii) member of Medibank with a level of cover that includes total joint replacement surgery; and viii) able to give informed consent and to participate in the interventions and assessment procedures.
Exclusion criteria are as follows: i) unable to speak or read English; ii) on waiting list for/planning knee/hip surgery in next 6 months; iii) previous joint replacement on affected hip; iv) recent hip surgery (past 6 months); v) doing regular leg strengthening exercise (at least once per week) each week for the past 6 weeks; vi) weight loss of > 2 kg over the past 3 months; vii) currently participating in a weight loss intervention; viii) planned bariatric surgery in next 6 months; ix) pregnancy or planned pregnancy; x) self-reported inflammatory arthritis (e.g.rheumatoid arthritis); xi) neurological condition affecting lower limbs; xii) unstable/uncontrolled cardiovascular condition; xiii) fall/s history (past 12 months) without GP clearance to participate; xiv) house-bound due to immobility without GP clearance to participate; and/or xv) answering 'yes' to any of the Exercise and Sports Science Australia stage 1 pre-exercise screening questions [26] without GP clearance to participate.
A clearance letter to participate in the study signed by a doctor is required from anyone who i) reports a fall (past 12 months); ii) is house-bound due to immobility; and/or iii) answers 'yes' to any of the Exercise and Sports Science Australia stage 1 pre-exercise screening questions.

Procedures overview
The trial phases are summarized in Fig. 1.Medibank will provide members with details to access an online questionnaire that will help determine preliminary eligibility.People deemed potentially eligible will then undergo telephone screening by the research staff to further explain the study, confirm eligibility, and obtain verbal consent.Those with body mass index (BMI) > 27 kg/m 2 will be asked to confirm their willingness to participate in the dietary intervention in the event that they are allocated to that group, and ascertain if they have conditions that preclude them from being on the VLED.A pre-exercise screening survey (Exercise & Sports Science Australia Adult Pre-Exercise Screening System) [26] will be included in the phone screen questionnaire to identify individuals who may be at an increased risk of falling or an adverse event related to Fig. 1 Participant flow through the randomised controlled trial exercising and therefore may require further assessment and GP clearance.Potential participants will be sent the Plain Language Statement (PLS) and Consent Form by email.If they have any questions or concerns regarding the contents of the PLS and/or Consent Form they will be encouraged to phone the researchers.Participants will provide consent online using REDCap prior to completing the baseline questionnaire or they will sign a paper-based consent form and return it via a replypaid envelope in the post or by scanning and emailing the document to the Trial Coordinator.For participants with bilateral hip pain, the most symptomatic eligible hip will be deemed the study hip with respect to the exercise intervention and outcome measurement.Throughout the trial, participants will not be restricted from using co-interventions and use of these will be measured as described below.

Randomisation, blinding and allocation concealment
Eligible participants will be randomised to receive either i) Better Hip program, or ii) web-based information (control).The randomisation schedule was computer generated by an independent biostatistician, using permuted random block sizes, stratified by participant BMI (> 27 kg/m 2 and ≤ 27 kg/m 2 ).The randomisation schedule is stored on a password-protected website (REDCap) at the University of Melbourne and will be maintained by a researcher not involved in either recruitment of participants or administration of primary/secondary outcome measures.Group allocation will be revealed by this same researcher after baseline assessment has been completed.Participants allocated to the Better Hip group will be randomly allocated to a physiotherapist and those who are eligible and choose to undergo dietary intervention will also be randomly allocated to a dietitian.
As this is a pragmatic trial, participants will not be blinded to group allocation.As participants are not blinded and the primary and secondary outcomes are participant-reported, by default the assessors of these outcomes are not blinded.Research staff administering and entering any participant-reported data will be blinded.The statistical analysis plan will be written and published while the biostatisticians are blinded.Main statistical analyses will be performed blinded to intervention group name.

Clinicians and training
Six physiotherapists and four dietitians were recruited and provided with standardised training, detailed trial manuals, videos and practice sessions aligned with best practices and recommendations by the National Institutes of Health Behaviour Change Consortium [27].All clinicians will be involved in regular meetings with research staff throughout the trial to prevent skill drift.
Physiotherapist training included: • Custom-designed self-directed e-learning modules on best-practice OA management, telehealth delivery and trial procedures, including the physiotherapy treatment protocol (estimated time commitment of 5 hours);

Interventions a) Better Hip program
The Better Hip program includes components based on best-practice for managing hip OA [5] and obesity [28].The personalised program is underpinned by the Chronic Care model [29], recommendations for design and evaluation of self-management programs [30] and behaviour change theory [31] and was adapted from our Better Knee, Better Me program for knee OA [21].The program aims to act through: i) improving knowledge and motivation regarding effective self-management; ii) increasing self-efficacy regarding OA self-management and diet control; iii) positive treatment beliefs about exercise and weight loss; and iv) positive outcome expectations from recommended treatment.
The Better Hip program embeds key behaviour change techniques as per Michie et al. [32] that are known to be effective for exercise and eating behaviours.These include goal setting, behavioural monitoring, feedback, positive reinforcement for progress, instruction, social support, problem solving, and action planning (Table 1).
Better Hip will be delivered by physiotherapists and dietitians using Coviu, a specialised telehealth video conferencing platform (www.coviu.com/en-au),accompanied by a suite of educational resources in hard copy.With the participant's consent, physiotherapists and dietitians will provide written communication to the participant's GP about their progress and outcomes.

Exercise/physical activity intervention
All participants will have six individual consultations with a physiotherapist.Consultations will be recommended to occur in weeks 1, 3, 7, 11, 16, and 21, but the exact timing will be discussed between each participant and their physiotherapist.The consultations will cover education about OA and discussion of non-drug treatment options, prescription of an individualised homebased strengthening program (to be undertaken three times per week) and physical activity plan, behaviour change support, and facilitation of other self-management strategies.Participants will also receive exercise resistance bands, an adjustable cuff weight, exercise/ activity log sheets and a wearable activity tracker to allow them to track and monitor their physical activity.
Prior to the initial consultation, participants will complete a pre-consultation survey asking them about their main problems and goals, and a brief history about their hip and other health problems.This will be provided to the clinicians prior to their first consultation with the participant, with the aim of making the first consultation more informed and efficient.
The initial physiotherapy consultation will be approximately 45 minutes in duration, and follow-up consultations will be approximately 30 minutes.During the initial consultations, a shared decision-making approach will be used to formulate appropriate goals and a tailored management plan.A custom-designed support "option grid" will be used to assist with shared decision-making regarding hip OA management options, and information sharing between the participant and physiotherapist.Education will be provided from a biopsychosocial perspective and will contain positive messaging to promote hope and optimism for the future, positive expectation of outcomes from active self-management strategies, and confidence in moving with and managing pain.Education will include discussion of a range of available interventions.Accurate information about the likelihood of future need for surgery will be provided and reasonable expectations about the role of hip joint replacement surgery in hip OA management will be established.
Participants' management plans will include the following components: a) A structured, personalised and progressive exercise program aimed specifically at increasing muscle strength; b) A tailored physical activity plan to increase incidental and general physical activity and reduce sedentary behaviour, including a daily step goal; c) Education and advice about other practical self-management strategies (e.g.activity modification, activity pacing, pain coping strategies, sleep advice); d) Customised education materials delivered in hard copy.
Based on their assessment of, and in discussion with, the participant, physiotherapists will prescribe 5 to 7 strengthening exercises primarily targeting the study leg from a pre-determined list and to be performed at home at least three times/week (see Appendix 1).During the consultations, the physiotherapists can provide real-time demonstration of exercises to participants via a bespoke website containing a video library of exercises contained within the "Exercise Booklet" and using the share-screen feature of Coviu.The target intensity for the strengthening exercises is 5 to 7 out of 10 (hard to very hard) on the modified Borg Rating of Perceived Exertion CR-10 scale [33] for strength training.Participants will be instructed that each exercise should be performed slowly and in a controlled manner.Progression will be guided in accordance with American College of Sports Medicine guidelines [34] by adjustments to repetitions, direction, and speed of movements; increasing resistance; and/or changing stance surface.Regular follow-up consultations between the participant and the physiotherapist to review progress, goals and the management plan and make modifications as required to ensure effective adoption of positive lifestyle changes and self-management strategies.The physiotherapist will also provide behaviour change support and assistance to overcoming obstacles to the participant enacting the agreed management plan.

Diet intervention
If participants have a BMI > 27 kg/m 2 , are aged < 80 years and do not have specific conditions which are likely to require medical supervision to participate in a ketogenic VLED (type 1 diabetes, type 2 diabetes requiring medication apart from metformin, using warfarin, stroke or cardiac event in the previous 6 months, unstable arrhythmia, constipation requiring medical intervention in the past 12 months, restriction of fluid intake or renal problems with estimated glomerular filtration rate < 30 mL/ min/1.73m 2 ), they can also opt to have six individual videoconferencing consultations with a dietitian to undertake a dietary weight loss intervention [20,21].Participants must also be willing to undertake the VLED using the meal replacement products to be eligible for the dietitian consultations.
The initial dietitian consultation will be approximately 45 minutes in duration with follow-up consultations approximately 30 minutes.It is recommended that the six consultations occur in weeks 2, 4, 6, 9 to 12, 14 to 17 and 19 to 23 but the exact timing will be agreed between each participant and their dietitian.During the consultations, appropriate weight loss goals will be agreed and a tailored management plan for losing weight developed.Conversations based on motivational interviewing principles and techniques will be used to develop readiness to change (motivation) and confidence to self-manage.Ongoing education, information and advice are key components of the intervention to optimally support weight loss.The dietitian will use follow-up consultations to review progress, goals and weight loss progress and together with the participant make modifications as required.The dietitian will assist in providing behaviour change support and assistance to overcome obstacles to the participant enacting the agreed weight loss plans.Core behaviour change techniques employed by the dietitian are specified in Table 1.
The diet intervention comprises two phases: 1) Intensive weight loss through a ketogenic VLED [35] for up to 16 weeks and aiming for ≥10% loss of body weight, as this is associated with clinically important improvements in knee OA pain and function [36,37].The ketogenic VLED involves replacing two meals, generally breakfast and lunch, with formulated meal replacement products (Optifast ® meal replacements, or if unavailable or the participant is vegetarian, Optislim ® ) provided at no cost to the participant.These products provide most of the vitamins, minerals, and metals required for optimal nutrition, and come as soups, shakes and bars in various flavours.
On the diet, one prepared meal (generally dinner) comprises protein (e.g.white or red meat, fish or seafood, eggs, or tofu) and non-starchy vegetables/salad.A small amount (i.e.

Enabling and behaviour change strategies/resources (see Tables 1 and 2)
Participants will be provided with resources to facilitate the management plans the physiotherapists will deliver during the sessions.These resources include: a welcome letter describing their involvement in the study; hard copy information booklets; four coloured therabands (red, green, blue, and black) and an adjustable cuff weight (0.5 to 5 kg) for performing strengthening exercises; and a wearable activity tracker to monitor daily step count.Physiotherapists will advise the participants to download the 'My Exercise Messages' app [39] which we developed and which is freely available from the Apple Store or Google Play.'My Exercise Messages' was created to help support people with OA stick to their weekly exercise  [40].Physiotherapists will advise the participants to use the app to track performance of their strengthening exercise program.Additional resources for those undertaking weight management include: • A plastic "portion plate" to help manage meal portion sizes and stick to the ketogenic VLED when preparing meals; • Another plastic "portion plate" to help manage meal portion sizes when transitioning to the healthy eating diet for weight maintenance; • A set of digital weight scales for those who do not already have access to scales; • Weight management 'how to' guide describing the ketogenic VLED, healthy food choices and portion sizes; • Ketogenic recipe book; • Food list pocket guide; • Workbook with information and templates to track weight, a food diary, tips to find a support person, identifying food triggers, planning for "at risk" situations, overcoming barriers, changing thought patterns, and monitoring hunger levels.
Resources and strategies that the dietitian will use to provide behaviour change support include: setting realistic goals; keeping a food diary; monitoring weight regularly (at least weekly); finding a support person to help; learning about healthy food choices and portion size; identifying food triggers; planning for 'at risk' situations; working out barriers and finding ways to overcome them; changing any negative thought patterns; engaging in relaxation, mindfulness and distraction techniques; monitoring hunger levels before, during and after meals to help identify physical and psychological hungers and strategies to overcome psychological hunger.

Web-based information (control)
This group will receive online information about hip OA and its management via a custom website accessible during their involvement in the study via password login.The Trial Coordinator will call participants allocated to the control group upon study enrolment to explain group allocation and how to access the website, after which the website URL and login details will be emailed to the participant.The website will include educational information about OA, recommended treatment options, exercise and physical activity, weight loss, managing pain, and optimising sleep, as well as links to external websites for further help and support (e.g.MyJointPain, pain-HEALTH, Musculoskeletal Australia).

Outcome measures
Participant-reported outcomes will be collected online via REDCap data capture platform at baseline, 6 months and 12 months.All participants who complete the 12-month re-assessment will be given a $50 gift voucher as compensation for the considerable time they have invested in the trial.An online survey for follow-up of primary and secondary outcomes will also be conducted at 2 years post randomisation.These longer-term results will be reported separately to the main trial results and will occur after analysis of the main trial data.
Primary outcomes are reliable and valid measures recommended for use in clinical trials of hip OA [41].These will be measured at baseline, 6 and 12 months, and include i) change in average severity of hip pain on walking in the past week measured on an 11-point NRS, where 0 = "no pain" and 10 = "worst pain possible"; ii) change in physical function subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) [42] with scores from 0 to 68, where higher scores indicate greater dysfunction.Conclusions about effectiveness will be based on the 6 month time point change in the primary outcomes.
The secondary outcomes will be measured at baseline, 6 and 12 months unless otherwise indicated and include: i) Change in Hip dysfunction and Osteoarthritis Out come Score (HOOS) [43] subscale of pain with nor malised scores ranging from 0 to 100, with 100 indicating no symptoms; ii) Change in HOOS [43] subscale of hip-related quality of life, with normalised scores ranging from 0 to 100, with 100 indicating better quality of life; iii) Change in HOOS [43] subscale of function, sports and recreational activities with normalised scores ranging from 0 to 100, with 100 indicating better function; iv) Change in self-reported body weight measured in kilograms; v) Change in health-related quality of life using the Assessment of Quality of Life instrument (AQoL-8D) [44], a 35-item instrument with scores ranging from − 0.04 to 1.0, with higher scores indicating better quality of life; vi) Change in physical activity levels evaluated using the Physical Activity Scale for the Elderly (PASE) [45] with scores from 0 to 400, where higher scores indicate greater levels of physical activity; vii) Perceived global rating of overall change in hip condition scored on a 7-point Likert scale from 'much worse' to 'much better' [46] at 6 and 12 months.Participants who indicate that they are "moderately better" or "much better" will be categorised as 'improved'; viii) Self-reported hip replacement procedures, where participants will be asked if they have had a hip joint replacement since their study enrolment on the study hip at 6 and 12 months; ix) Willingness to undergo hip replacement surgery self-rated using a 5-point Likert scale with anchors "definitely not willing" and "definitely willing".Participants indicating 'probably willing' or 'definitely willing' will be classified as 'willing'; x) Use of oral pain medications self-reported and defined as one or more of analgesics (paracetamol combinations) and/or oral non-steroidal antiinflammatory drugs and/or oral glucocorticoids and/or oral opioids taken at least once a week in the prior month for hip pain.

Other measures
Other measures to be collected at baseline, 6 and 12 months include: i) Hip Osteoarthritis Knowledge Scale [47], scored from 11 questions on a 5-point Likert scale with scores ranging from 11 to 55 where higher scores indicate greater knowledge about OA; ii) Attitudes toward self-management using the Patient Activation Measure (PAM-13) [48], scored from 13 statements rated on a 4-point Likert with higher scores indicating greater patient activation; iii) Brief Fear of Movement Scale for Osteoarthritis [49], scored from 6 statements on a 4-point Likert scale with scores ranging from 6 (minimal fear) to 24 (maximal fear); iv) Arthritis self-efficacy scale (pain subscale) [50], scored from 5 items on a 10-point NRS with the total presented as an average of the 5 items where higher scores indicate higher self-efficacy.

Treatment adherence
A number of adherence measures will be collected from participants allocated to the Better Hip program.These include: i) Number of consultations with the physiotherapist, taken from consultation notes (0 to 6), reported as the mean (standard deviation) as well as the number and proportion of participants deemed to be adherent (≥4 consultations); ii) Duration of physiotherapist consultations (minutes); iii) Number of eligible participants (BMI > 27 kg/m 2  and no exclusions for ketogenic VLED) choosing to undergo dietary intervention; iv) Number of consultations with the dietitian for those undergoing dietary intervention, taken from consultation notes (0 to 6), reported as the mean (standard deviation) as well as number and proportion of participants deemed to be adherent (≥4 consultations); v) Duration of dietitian consultations (minutes); vi) Adherence to the strengthening exercise program self-rated at 6 and 12 months on an 11-point NRS in response to the question: "Over the past 6 months, how much did you adhere to the strengthening exercise program provided to you by the physiotherapist?" with responses from 0="not at all" to 10="completely as instructed"; vii) Number of days strengthening exercises were performed in the previous fortnight self-reported at 6 and 12 months; viii) Perceived intensity of the strengthening exercise program self-rated at 6 months using the modified Borg Rating of Perceived Exertion CR-10 scale [33].Participants will be asked "When performing your strengthening exercises over the past six months, how hard do you feel you have been working on average?"Scores range from 0 to 10 with higher scores indicating higher perceived intensity of exercise; ix) Adherence to a physical activity plan self-rated at 6 and 12 months on an 11-point NRS in response to the question: "Over the past 6 months, how much did you adhere to the physical activity plan provided to you by the physiotherapist?" with responses from 0="not at all" to 10="completely as instructed".x) Adherence to a weight management plan (for those undergoing dietary intervention) self-rated at 6 and 12 months on an 11-point NRS in response to the question: "Over the past 6 months, how much did you adhere to the weight management plan?" with responses from 0="not at all" to 10="completely as instructed".

Other process measures
A number of other self-reported process measures will be collected at program scored on a 5-point Likert scale with response options from "extremely unsatisfied" to "extremely satisfied" (those scoring "moderately" or "extremely" classified as "satisfied") and; likelihood of recommending the Better Hip program to someone else with the same condition scored on a 5-point Likert scale with response options from "extremely unlikely" to "extremely likely" (those scoring "moderately" or "extremely" classified as "likely").The control group will also be asked to self-report at 6 and 12 months whether they have undertaken any regular exercise for their hip (defined as 2 or more times per week for at least 1 month) and the type of such exercise.

Descriptive measures
Baseline self-reported descriptive measures include age, height, BMI, gender, country of birth, ethnicity, geographical location, education level, current employment status, occupation, weekly earnings before tax, symptom duration, time since first visit to doctor for hip pain, comorbidities assessed using the Self-Administered Comorbidity Questionnaire [51], history of hip surgery, and treatment expectation assessed on a 5-point ordinal scale.

Consultations with physiotherapists and dietitians in the
Better Hip group will be audio-recorded and files will be stored on a secure password-protected cloud-based system.Bespoke semi-structured consultations notes will be completed online on REDCap ™ by physiotherapists and dietitians for each consultation.Notes will be scrutinised by research staff for clinician adherence to protocols.Fidelity, as determined from the clinician consultation notes, will be reported as the number and proportion of participants where the physiotherapist: i) prescribed a strengthening exercise program; and ii) prescribed a physical activity plan, and where the dietitian: i) discussed the use of meal replacements; ii) discussed ketogenic principles for preparing the third meal during the ketogenic VLED phase; iii) discussed transition to healthy eating; and vi) discussed healthy eating principles.The number and proportion of participants where the clinicians delivered the core behaviour change techniques will be reported for: goal setting; problem solving; review behaviour goals; feedback on behaviour; feedback on outcomes of behaviour; instruction on how to perform the behaviour; and information about health consequences.

Adverse events
Related adverse events are defined as "any problem experienced in the study hip or elsewhere in the body deemed to be a result of participating in the trial and at least one of i) caused negative/adverse symptoms/effects for two days or more, and/or ii) resulted in the participant seeking treatment from a health professional".Adverse events will be ascertained by survey questions to participants at 6 and 12 months.
A serious adverse event is defined as any untoward medical occurrence that; i) results in death; ii) is lifethreatening; iii) requires hospitalisation or prolongation of existing inpatient hospitalisation; iv) results in persistent or significant disability or incapacity; v) is a congenital anomaly or birth defect, or; vi) any other important medical condition which, although not included in the above, may require medical or surgical intervention to prevent one of the outcomes listed.Due to the low-risk nature of the interventions in this trial, related serious adverse events are extremely unlikely.Participants, dietitians and physiotherapists will be advised to report any serious adverse events to the Trial Coordinator as soon as they can by telephone or email, which will be documented and reported to the Sponsor (University of Melbourne) within 24 hours of the research staff becoming aware of the event.
Any adverse events reported by telephone/email or in questionnaires will be reported to the Internal Trial Monitoring Committee, including the Chief Investigator who will be responsible for deciding what action, if any, is needed on a case-by-case basis.All recorded adverse events will also be reported as blinded data to the Data Safety and Monitoring Committee for the study.The Internal Trial Monitoring Committee and the Data Safety and Monitoring Committee will collectively determine whether reported adverse events are likely to be related to the intervention.
We will report the number and proportion of participants who: withdraw from the study due to a related adverse event; experience one or more serious related adverse events and their types; and experience one or more non-serious related adverse events and their types.

Health economic measures and evaluation
We will conduct economic evaluations (led by AH) with results reported separately to the main trial outcomes.These will use data from Medicare/Pharmaceutical Benefits Scheme and Medibank and will assess and compare cost-effectiveness of Better Hip including: i) cost per extra person with a clinically significant improvement in pain and function; and ii) per quality-adjusted life years (QALY) gained for Better Hip group compared to control at 12 months.
Health care expenditure for each participant will be extracted from Medicare Benefit Schedule (MBS), Pharmaceutical Benefit Scheme (PBS) and Medibank data for 12 months prior to baseline and for 24 months after enrolment.The MBS collects information on medical visits and procedures, and the associated costs.The PBS collects information on prescription medicines filled at pharmacies, and Medibank collects information on member hospital, medical and ancillary services for claims made against their Medibank membership.We will seek participants' consent to access their Medibank data and their MBS and PBS data from the Australian Government Department of Human Services.Public hospital admission/attendance will be self-reported at baseline, 6 and 12 months via a bespoke questionnaire asking number, reason for and length of public hospital admissions in the last 6 months.Participants will also be asked if they attended an emergency department and/or any outpatient appointments at a public hospital.
For those in employment, work productivity will be assessed using the World Health Organisation Health and Work Performance Questionnaire (clinical trials version) [52].
QALYs will be calculated based on utility scores using the AQoL-8D at baseline and 12 months.Difference in health care usage and productivity lost between baseline and 12 months will be compared, as will the association between utility gains (AQoL-8D) and productivity.

Trial sample size
We aim to detect the minimal clinically important difference (MCID) over 6 months on the two primary outcomes of i) change in hip pain during walking (NRS) and ii) change in physical function (WOMAC).The MCID in OA trials is a 1.8-unit pain change [53] and 6-unit function change [42].The sample size calculation accounts for potential clustering by physiotherapists in the Better Hip group.Based on our research [54], we assume a conservative between-participant standard deviation of 2 pain units and 11 function units, correlations between baseline and 6-month scores of 0.25 for pain and 0.4 for function, an intra-cluster correlation of 0.05 and 5 physiotherapists treating participants.With these parameters, we need 90 per group to achieve 80% power to detect the MCID in function at a 0.025 significance level (due to two primary outcomes).This gives > 99% power to detect the MCID in pain.Allowing for 15% attrition, we will recruit 106 people per group (in total n = 212).

Data analysis plan
We will use intention-to-treat analyses.For the two primary outcomes and other secondary continuous outcomes, mean differences in change over time between groups will be estimated via separate linear mixed-effects models, with random effects for participants and physiotherapist.Models will be adjusted for baseline outcomes and BMI (> 27 kg/m 2 and ≤ 27 kg/ m 2 ).Terms for time and treatment will be included, and their interaction, and results reported as mean difference in outcomes at 6 months (primary timepoint) and at 12 months between the Better Hip group and control group.These models provide valid inference in the presence of missing data if the data are missing at random.An analysis will be conducted using the deltaadjustment method under the pattern-mixture modelling framework in the context of multiple imputation to assess sensitivity to missingness not at random.To aid clinical interpretation, the primary outcomes will also each be dichotomised into those who do and do not achieve the MCID in improvement in pain (1.8 NRS units) and function (6 WOMAC units).Counts and percentages of participants achieving the MCID in improvement in pain and function will be reported in each treatment group at 6 and 12 months.For binary outcomes (clinically-relevant improvement, global change, participants using any oral pain medication at least once per week, participants undergoing a hip replacement procedure, willingness to have hip replacement surgery), logistic mixed-effects models will be fitted adjusted for the outcomes at baseline where able and BMI (> 27 kg/m 2 and ≤ 27 kg/m 2 ), with random effects for participant and physiotherapist, and results reported as risk ratios and risk differences at 6 months between the treatment groups.Analysis of moderation of the treatment effect by pre-specified potential moderators (baseline willingness to have surgery, BMI) on the two primary outcomes will be assessed by including interactions between moderators and the treatment group in the regression models.For all between-group comparisons, 95% confidence intervals and p-values will be reported.Standard diagnostic plots will be used to verify model assumptions.

Patient and public involvement
End-users and stakeholders were engaged in developing the research question, study methodology, and intervention components.Representatives from our partner organisations, Medibank, Coviu, the Australian Physiotherapy Association and Dietitians Australia as well as a consumer with hip OA (JM) provided input into the research question and study protocol, and were also named Associate Investigators on the grant application.The Medibank marketing team conceived the name of the program.A consumer (JM) provided feedback about the length and ease of access of the initial proposed questionnaire battery, and was also named an Associate Investigator on the grant application.Four physiotherapists provided specific input into the design of the hip strengthening exercises while two consumers participated in the filming/production of the exercise videos.Coviu provided clinician and researcher training in the use of the online consultation platform and feedback on the physiotherapist and dietitian manuals and participant resources.The 'My Exercise Messages' app had extensive iterative engagement during the development of the behaviour change message library and app which has been previously described [39].A dietitian from Dietitians Australia and an endocrinologist (PS) provided input into the design of the portion plate.Consumers and clinicians provided input and feedback on the participant resources.

Timelines
The Human Research Ethics Committee of The University of Melbourne gave ethical approval on 23rd February 2022.We prospectively registered the trial with the Australian New Zealand Clinical Trials Registry on 24th March 2022.Participant recruitment commenced in June 2022.Recruitment is expected to be completed in June 2024.The main trial is due for completion in June 2025 when all participants have completed 12-month data.

Dissemination
Study findings will be disseminated through conference presentations and publication in peer-reviewed journals as well as via our Centre website, knowledge translation network, media and social media including a study infographic.If the Better Hip program is found to be effective, Medibank will likely scale up the program as an offering across its broad membership base, by adapting implementation plans set in place with the previous scale-up of the Better Knee, Better Me program.Trial e-learning modules and clinician manuals will be made freely available on FutureLearn (a digital education platform) and via our Centre website for accessible clinician professional development.Downloadable patient resources will also be made freely available for clinicians and consumers.The International Committee of Medical Journal Editors recommendations for authorship will be followed.

Discussion
This protocol describes the background, aims and methods for a two-group, parallel design RCT aiming to evaluate the effectiveness of a 6-month telehealth-delivered, cliniciansupported lifestyle management program (Better Hip) on the primary outcomes of change in hip pain while walking and physical function at 6 months, compared with an informationonly control for people with hip OA.The effects of the program on these primary outcomes at 12 months as well as on other clinical outcomes at 6 and 12 months will also be evaluated.A range of other measures will provide insights into the safety, feasibility, acceptability of and engagement with this innovative remotely-delivered model of service delivery that focuses on core recommended hip OA treatments of education, exercise/physical activity, and for those with overweight and obesity, weight loss.A separate health economic evaluation at 12-months will inform implementation decisions while a separate survey to the main trial will follow-up participants at 2-years to determine longer-term outcomes.Such a service model has the potential to increase patient access to evidence-based lifestyle management programs.

Double to single leg bridge
Lie on your back with your knees bent and your feet flat on the floor/ firm bed.

Table 1
Main behaviour change techniques incorporated into the program** * Based on the Behaviour Change Technique Taxonomy v1 [32] † Core behaviour change techniques, delivery audited by clinician self-report Included/incorporated into printed participant resource booklets Provided by clinician during video consultations Incorporated into trial procedures (e.g.written communication to participant's GP about their progress) Physical resources provided to participants (e.g.activity tracker, portion plates, My Exercise Messages app) ** Adapted from: Bennell KL, Lawford BJ, Keating C, et al.Comparing Video-Based, Telehealth-Delivered Exercise and Weight Loss Programs With Online Education on Outcomes of Knee Osteoarthritis : A Randomized Trial.Ann Intern Med.Feb 2022;175(2):198-209

Table 2
Summary of resources provided to participants in the Better Hip group a [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]KL, Keating C, Lawford BJ, et al.Better Knee, Better Me ™ : effectiveness of two scalable health care interventions supporting self-management for knee osteoarthritis-protocol for a randomized controlled trial.BMC musculoskeletal disorders.2020;21[1]:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Side lying hip adductionLie on your side on your study hip with a small rolled up towel between your rib cage and waist.Place your non-study foot in front of your knee so it is out of the way of / not on top of your study leg.(If too difficult, just lie with legs one on top of the other).Your study leg will be straight, toes pulled up towards you, knee facing forwards.Keeping your body very still, think about sucking your thigh/ leg up into the hip joint socket and slowly lift the study leg up off the bed.Keep your knee straight.This is a very small movement and there is no need to overdo ityou are aiming to simply get your foot off the ground.You should feel the work in your inner thigh of the study leg.Slow controlled lift up, slow controlled lower down.Lie on your front on a firm surface with a resistance band around the ankle of your study leg.Attach the band to a secure object like a table leg or bed.Bend the knee on your study leg to 90 degrees and allow the lower leg to fall out with the pull of the resistance band.Keep your thighs in the same position while you rotate the lower leg inward to the midline, pulling against the band.Hold for 3 seconds in this position.Control the leg as you rotate it back to the starting position.into the design of the hip strengthening exercise protocol: Andrew Dalwood, Jonathan Dodd, Daniel Zwolak and Joshua Priest, as well as our partner organisations Medibank, Coviu, the Australian Physiotherapy Association and Dietitians Australia.The University of Melbourne, Parkville, Victoria, 3010, Australia Telephone: +613 8344 2163 Email: clini caltr ials-gover nance@ unime lb.edu.au input